Cannabis Users at Greater Risk for Heart Rhythm Disorder

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Several scientific studies have examined the short and long-term effects of cannabis use. One such study recently put forth compelling evidence that there may be a connection between cannabis use and users developing the heart rhythm disorder atrial fibrillation (A-fib).

What the Findings Show

Researchers at the University of California, San Francisco, found that marijuana use may increase the risk of users experiencing the heart rhythm disorder atrial fibrillation by 35%. This finding is one of many in recent years that suggest cannabis consumption may have serious, negative health implications.

There are varying theories about why cannabis may put users at greater risk for A-fib. Currently, the researchers believe that the inhalation of combustible products triggers an inflammatory response, and acute inflammation heightens A-fib risk. The researchers also posited that lung irritants such as pot smoke could aggravate areas of the heart that are particularly vulnerable to arrhythmia, given that blood from the lungs flows directly to the area of the heart where A-fib begins.

A-fib is no minor inconvenience, either. A-fib is an abnormal pumping rhythm of the heart caused by electrical disturbances in the heart’s upper chambers, called the atria. In severe cases, blood clots can form in the atria due to A-fib, and those clots can break off into the bloodstream, causing strokes. A-fib is believed to cause more than 150,000 fatal strokes per year.

The researchers involved in the study also found that other drugs increase users’ risks for A-fib, namely methamphetamine, cocaine, and opioids. However, medical experts had already surmised the connection between those hard drugs and A-fib. The findings regarding cannabis and A-fib were previously unknown. Quoting lead researcher Dr. Gregory Marcus, a professor of medicine at the University of California, San Francisco, “These data are sufficiently compelling to suggest that cannabis users suffering from atrial fibrillation should at least experiment with cessation to see if it indeed has a meaningful effect on their particular arrhythmia. Once one has had an episode of atrial fibrillation, I find that patients are often especially eager to identify anything they can do to avoid subsequent episodes.” Since many states are considering cannabis legalization, it would be beneficial to voters if public health officials and policymakers informed them of the potentially serious risks of using cannabis.[2]

Known, Harmful Effects of Cannabis

The findings cited above suggest a connection between cannabis use and atrial fibrillation, but that is only one of the many unwanted health effects now associated with cannabis. Some of the short-term effects of cannabis use include:

  • Changes in mood
  • Impaired memory
  • Altered sense of time
  • Impaired body movement
  • Struggles with problem-solving
  • Difficulty with cognitive function
  • Hallucinations, delusions, and psychosis
  • Seeing different colors and perceiving things that are not there

Sadly, cannabis use, when done over time, also has some serious long-term effects. For example, when people repeatedly use cannabis as adolescents, teenagers, or young adults, the drug can impair thinking, memory, and learning functions. Cannabis can also affect how the brain builds connections between the areas of the brain that are necessary for these functions.

Marijuana effect

Other research suggests people who use cannabis long-term suffer a decline in general knowledge and verbal ability. It is believed this loss of function is equivalent to four IQ points. There is no indication that cognitive function returns when one halts cannabis consumption.

Long-term cannabis use can lead to breathing problems, cardiovascular difficulties, and increased nausea and vomiting. Some users may even develop Cannabinoid Hyperemesis Syndrome, a medical condition that causes users to experience regular cycles of severe nausea, vomiting, and dehydration. Sometimes these experiences can be so severe that they require emergency medical attention.

Another critical issue regarding cannabis is potency. According to the DEA, cannabis seized by law enforcement today is at least 15% THC, whereas cannabis seized in the 1990s was closer to 3% THC, which is a 500X increase in potency in just 30 years. People who take cannabis with high THC levels may experience acute psychosis, hallucinations, delusions, and a loss of personal identity. And given that cannabis potency has soared in recent years, the risk of experiencing harmful effects has increased.

As Legalization Efforts Continue, Voters Should be Informed of Cannabis Risks

People should know about the adverse effects of cannabis, especially if they’re going to vote on its legalization. To that point, the 2022 midterm elections saw cannabis on the ballot in five states: Arkansas, Maryland, Missouri, North Dakota, and South Dakota.

All five states had ballot proposals that offered voters the prospect of legal recreational cannabis. Residents rejected the ballot proposals in Arkansas and the Dakotas, but the initiatives passed in Maryland and Missouri. Looking to the future, more states will have ballot proposals suggesting decriminalization, medicinal use legislation, or complete legalization of cannabis for recreational use. As the marijuana issue is increasingly given to the voters to decide, Americans should ensure they are fully informed on the potentially harmful effects of cannabis before they vote on it.


  • EHJ. “Cannabis, cocaine, methamphetamine, and opiates increase the risk of incident atrial fibrillation.” European Heart Journal, 2022.
  • USNews. “Marijuana, Meth, Cocaine Use Can Help Trigger Dangerous A-Fib.” U.S. News, 2022.
  • NIDA. “Cannabis (Marijuana) Potency.” National Institute on Drug Abuse, 2021.
  • NIDA. “Cannabis (Marijuana) DrugFacts.” National Institute on Drug Abuse, 2019.
  • CNN. “Marijuana legalization on the ballot in these states: Here’s what voters decided.” CNN, 2022.



After working in addiction treatment for several years, Ren now travels the country, studying drug trends and writing about addiction in our society. Ren is focused on using his skill as an author and counselor to promote recovery and effective solutions to the drug crisis. Connect with Ren on LinkedIn.